Method and system for providing information for a mobile terminal

ABSTRACT

A mobile terminal, and an information providing method and system which immediately provides information, which the user of the mobile terminal desires, for the mobile terminal. Areas and related service information are stored in corresponding relationship in a database. An information server which includes means for calculating the area of a destination of the mobile terminal loads information on the destination area from the database to the mobile terminal which moves toward the destination area, using radio communication means before the mobile terminal arrives at the destination area.

BACKGROUND OF THE INVENTION

The present invention relates to a small lightweight portable computercalled a mobile terminal, and an information providing method and systemin which an information server provides the mobile terminal withappropriate service information which the mobile terminal desires andwhich is related or strongly correlated to an area where the mobileterminal is present, depending on the position of the mobile terminal.

The invention which provides the user of a mobile terminal with veryconvenient meticulous services by using information on the position ofthe terminal is disclosed in JP-A-5-102906, entitled "MobileCommunication System". In this invention, the user who is able to knowhis position, using a car navigation system, sends information on theuser's position through a car telephone to a service center anddownloads the newest information on a possible traffic jam and/or a mapconcerning his position from the service center. Another inventiondiscloses that without receiving information on the user's positionexpressly from the user, an area in which the user is present ispresumed on the basis of a position of a base station for cartelephones, and service information on a possible traffic jam, etc., inthat area is downloaded.

In the above conventional techniques, when the newest map data is to beobtained to know the newest route situation on route interruption due toroad works and/or opening of a new route, the data transmission ratethrough the car telephone is low, for example 2.4 kbps whereascompressed map data still reaches several tens of kilobytes or more.Thus, the car travels about several kilometers during only the timetaken for sending the retrieved map data and necessary information cannot be obtained on a real time basis. Actually, radio transmission bythe car telephone provides low quality data and a bit error is likely tooccur. For ensuring purposes, re-transmission of data is required andhence it is difficult to receive necessary information on a real timebasis.

In the above conventional inventions, for example, information on theoccurrence of a traffic jam over a specified length of a specified roadin a specified area in the vicinity of user's position is given to userin response to the user's inquiry. Thus, unless the user has a knowledgeabout a route in which a traffic jam is likely to occur, the user doesnot know the timing in which the user inquires about such information,would be involved in the traffic jam, and wishes to obtain informationas to how many hours it would take from the occurrence of the trafficjam to its disappearance. However, the user should rather know whichroute the user should select to reach his destination in a minimum timewhen a traffic jam occurs on his selected route than he knows how muchtime it would take from the implication of the user into the traffic jamto the clearance of the jam.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide acommunication method capable of providing the user with properinformation on a real time basis and a mobile terminal preferred forcarrying out this communication method.

Another object of the present invention is to provide a communicationmethod which transfers proper information to the user at appropriatetiming and a mobile terminal preferred for carrying out thiscommunication method.

In order to achieve the above objects, the present invention loadsservice information beforehand on a mobile terminal. Specifically, thepresent invention provides a method of providing information from aninformation server to a mobile terminal in a system which includes themobile terminal, the information server being connected to a database, anetwork connected to the information server, and a terminal connected tothe network for providing various information for the informationserver, including the steps of connecting the mobile terminal to thenetwork and when information on the current place and destination of themobile terminal is input, and reporting the input information on thecurrent place and destination to the information server through thenetwork; causing the information server to determine the whole areacontaining the current place and destination of the mobile terminal whenthe information server receives from the mobile terminal a report ofinformation on the current place and destination of the mobile terminal,and to send service information containing positional informationcorresponding to the whole area through the network to the mobileterminal; and causing the mobile terminal to store in storage thereceived service information containing positional informationcorresponding to the whole area, to cut the connection to the networkand to output the beforehand stored service information in accordancewith the user's request.

The present invention also provides a method of providing informationfrom an information server to a mobile terminal in a system whichincludes the mobile terminal, the information server connected to adatabase, a network connected to the information server, and a terminalconnected to the network for providing various information for theinformation server, wherein the mobile terminal is connected to aportable telephone set so as to be connected to the network, andconnected to a GPS which stores information on its position periodicallyin a memory, and when the mobile terminal receives information on thepresent place of the GPS from the GPS and input information on adestination of the mobile terminal, the mobile terminal informs throughthe network the information server of the information on the currentplace and the destination of the mobile terminal; when the informationserver receives from the mobile terminal information on the currentplace and destination, the information server determines the whole areacontaining the current place and destination, and sends serviceinformation containing positional information corresponding to the wholearea through the network to the mobile terminal; and the mobile terminalstores in storage the received service information containing thepositional information corresponding to the whole area, cutting theconnection to the network, and outputs the beforehand stored serviceinformation in accordance with the user's request.

According to the present invention, in the above method, the mobileterminal sends information on its current place periodically through thenetwork to the information server, and the information server sends theservice information periodically through the network to the mobileterminal.

According to the present invention, in the above method, when theinformation server receives the information on the current place of themobile terminal from the mobile terminal, the information servercompares the service information on the area sent previously to themobile terminal and service information on an area to be sent this time,and when the service information on the area to be sent this time isdifferent from that sent previously, the information server sends theservice information on the area to be sent this time through the networkto the mobile terminal.

According to the present invention, in the above method, the mobileterminal produces history information by storing information on theposition of the mobile terminal periodically, determines the next areafrom the produced history information, reports information on the nextarea to the information server through the network and inquires of theinformation server service information on the next area.

According to the present invention, in the above method, the serviceinformation on the whole area containing the current place anddestination of the mobile terminal sent from the information server isstored as compressed data in external storage of the mobile terminal,the service information on the next area stored in the external storageis read when the determined service information on the next area is notstored in a RAM of the mobile terminal, the read service information isdecompressed, and the decompressed information is stored in the RAM ofthe mobile terminal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a sequence of operations performed between a mobileterminal and an information server;

FIG. 2 illustrates the structure of hardware of a mobile terminal in anavigation system;

FIG. 3 illustrates the composition of the navigation system;

FIG. 4 illustrates a data format of service information stored in adatabase;

FIG. 5 illustrates the relationship between the position of a mobileterminal and its areas;

FIG. 6 shows a data format of service information when sent;

FIG. 7 illustrates the structure of a display screen for navigationinformation in the mobile terminal;

FIG. 8 illustrates the composition of a mobile terminal system;

FIG. 9 illustrates a sequence of operations performed between a mobileterminal and an information server;

FIG. 10 illustrates a sequence of operations performed between a mobileterminal and an information server;

FIG. 11 illustrates a sequence of operations performed between a mobileterminal and an information server;

FIG. 12 illustrates a technique for specifying an area whose informationis to be loaded in the current area;

FIG. 13 shows an information structure which will be referred to whencompressed data is loaded;

FIG. 14 is a chart illustrating the principles of the present inventionused when compressed data is loaded from its disk;

FIG. 15 illustrates an automatic power off logic of storage having arotating system;

FIG. 16 shows a format of service information spread in primary storageof a mobile terminal;

FIGS. 17A, 17B each illustrate the relationship between the present andnext areas and a method of constructing an area;

FIG. 18 illustrates a management table of an information server;

FIG. 19 illustrates a sequence of operations performed between a mobileterminal and information server;

FIG. 20 illustrates a sequence of operations performed between a mobileterminal and information server;

FIG. 21 illustrates the relationship between the moving direction of amobile terminal and the next area;

FIG. 22 illustrates a logic for changing an information quantity to beloaded depending on the speed of a mobile terminal; and

FIG. 23 illustrates application of the present invention to a remotebusiness support system.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 2 illustrates the structure of hardware of a mobile terminal in thepresent system. The mobile terminal 20 includes a CPU (CentralProcessing Unit) 10, which communicates with a RAM (Random AccessMemory) 12 and a ROM (Read Only Memory) 11 as the main storage and alsowith a liquid crystal panel input/output controller 14, a card adapter15 and a modem unit 16 as peripheral input/output units through a systembus 50. A bus controller 13 controls the communication between CPU 10and related peripheral input/output devices. The liquid crystal panelinput/output controller 14 is connected to a panel 17 which is a displayand an input unit for a pen 18. The card adapter 15 is connected to aremovable memory card 19 as an external storage. The modem unit 16 isconnectable to a telephone line by which the mobile terminal 20communicates with a remote computer system.

FIG. 3 is a block diagram of the present system. Reference numeral 21denotes an information server which is connected to a data base 22. Theinformation server 21 is computer which is the same in basic structureas the mobile terminal 20 excluding in storage capacity and aninput/output controller thereof for a database 22. Reference numeral 23denotes a service information provider for the information server 21 andincludes various shops such as restaurants and/or convenience stores.Reference numeral 24 denotes a traffic information center which hasgripped the current situation of roads/routes. The mobile terminal 20 isconnected through a public network 25 to the respective devicesmentioned above. The information server 21 receives traffic jaminformation from the traffic information center 24 and serviceinformation such as map information and/or article information for theuser from the shops 23 and stores them in the database 22.

FIG. 4 illustrates a data format used in the database 22. The serviceinformation in the present invention is service information using animage, for example, of a road map, voice service information utteredwhen a map guidance is read, and text service information such as amessage display for a shop guide. In any rate, as long as a method isused which stores encoded data in the database 22 in spite the type ofthe service information, service information of any type of service maybe stored. Information which identifies the classification of theabove-mentioned service information is described in the serviceclassification of FIG. 4. Retrieval key information provided tofacilitate the search of an area with positional information isdescribed in a retrieval key section. Information indicative of thestorage position and range of data in the database 22 is described in anaddress section.

Referring to FIG. 5, the relationship between service information andretrieval keys for the respective data in the database 22 will besupplemented. A region of interest is divided into areas which are thennamed, in correspondence to positions on a map. For example, the presentplace where a mobile terminal is present is named an "e-B area". Amapping table which specifies an appropriate area from information onthe position of the mobile terminal is provided so that positionalinformation and areas are placed in corresponding relationship. The nameof this area is stored in the retrieval key section.

FIG. 1 shows a sequence of operations in which the mobile terminal 10receives information service involved in the present invention.

Assume that the user goes out for driving. First, the user desires toknow the newest information about a road through which the user arrivesat his destination when he selects that road before he starts out(S100). He connects the mobile terminal 10 to the telephone line andstarts up a program which inquires the situation of the road, using themobile terminal 10. In this case, he inputs data on his current addressand the destination address in accordance with the instruction of theprogram (S102). The started-up inquiry program calls the informationserver 21 over the telephone line and establishes a connection which isa communication channel for logical data communication between themobile terminal 10 and the information server 21 (S104). The mobileterminal 10 then informs the information server 21 of the positionalinformation on the user's current place and destination input by theuser (S106). As shown in FIG. 5, the information server 21 which hasreceived the positional information determines the areas of the user'scurrent place and destination and then determines the range of areas tobe retrieved. In the present embodiment, assuming now that the currentplace and destination are areas e-B and b-E, respectively, the range ofareas to be retrieved are areas e-B, e-C, e-D, e-E, d-B, d-C, . . . andtakes the form of a rectangle in which the current place and destinationare present as the diagonal areas. These areas are used as retrievalkeys to retrieve data including the appropriate service information fromthe data base (S108). The information server 21 then sends the retrievedservice information to the mobile terminal (S110).

FIG. 6 shows a format of data sent from the information server to themobile terminal. In this format, the information which controls acommunication protocol is at the head of the format and accompanied bydata retrieved from the database. In this case, information on theposition (range) of an area to which the appropriate service informationis related is sent in place of the retrieval keys. Receiving thisinformation, the mobile terminal converts this information to aretrievable form in accordance with the positional information of theservice information and stores that converted information in the memorycard (S112). After the service information has been transferred, theconnection is cut off (S114). Informed that downloading of the serviceinformation has been completed by the inquiry program and that theconnection has been cut, the user cuts the mobile terminal from the lineand starts for the destination while carrying the mobile terminal(S116).

When the user desires to know the situation of a point on the road tothe destination during travelling, the user refers to necessaryinformation, for example, on traffic jams by retrieving the serviceinformation downloaded beforehand (S118).

FIG. 7 illustrates a service information reference screen of the mobileterminal 20. The present screen is composed of various windows whichwill be described next. First, a whole map window 701 will be described.This displays in a rough map all the areas related to the downloadedservice information. The map is divided into blocks having apredetermined side length in which the present place (in this example,the starting point) and the destination are indicated. In addition, ablock indicated by a detailed map window 702 to be described later isrecognizable. The window 702 displays the detailed map of a blockselected in the whole map window 701. Road information on the course tothe destination and traffic jams are superimposed and displayedgraphically on the map. A message window 703 displays textized serviceinformation. A menu window 704 displays control icons and retrievalinformation icons for a service information retrieval program as aprogram of the present mobile terminal 20. The control icons expressesby images the commands for executing the start-up and termination of thepresent program by selecting the appropriate ones of those icons.

The retrieval information icons are, for example, gas stations,restaurants, parking places, resting places and drive-ins. By selectingany one of these icons, its related information on its position, priceand features) is displayed as image data on the detailed map window 702.Text data is displayed on the message window 703. When the relatedinformation involves voice data, a voice output unit may be connected tothe mobile terminal 20 such that the voice data on the relatedinformation may be communicated as an announcement to the user byselecting the appropriate icon.

In this embodiment, service information is loaded on the mobile terminal20 at the starting point before the user starts for his destination.Thus, this system is suitable for use when the destination ispredetermined or relatively near to the starting point and not changed.When the destination is far away from the starting point and it takesmuch time for the user to reach the destination, service informationsuch as traffic jams loaded beforehand may get old and not express thereal situation of the place where the mobile terminal is present. Whenthe initial destination is changed for some reasons, beforehand loadedservice information such as traffic jams to the destination may beuseless. In order to avoid such situation, the user may stop at a nearbypublic telephone with data communication terminals at constant intervalsof time or distance or when the user changes his destination to accessthe information server 21 to download the newest service information orservice information to the changed destination. Of course, it isnecessary that the positions of the public telephones should becontained in the service information and that the user is able to referto such service information.

An embodiment, in which the access position is not limited to a fixedone, using radio communication means will be described next.

FIG. 8 illustrates a system structure. Reference numeral 30 denotes acar telephone which is connected to the mobile terminal 20 to act as anintermediary for data communication between the information server 21and the mobile terminal 20. Reference numeral 40 denotes a GPS (GlobalPositioning System) which is connected to the mobile terminal 20 and hasthe function of calculating its position with high accuracy (with anerror of several meters) by receiving radio signals from a plurality ofsatellites. GPS 40 calculates its position periodically, stores theobtained data in its memory (not shown) and delivers the stored data onits position to the mobile terminal 20 in response to a request from themobile terminal 20. At this time, GPS 40 informs the mobile terminal 20of information on the position of GPS 40 in longitude and latitude.

FIG. 9 shows a download sequencing operation about service informationperformed when the destination is changed on the way to the destination.The difference in sequencing operation between FIGS. 1 and 9 will bemainly described. The user needs the newest information on the situationof its changed destination (S200). Confirming that the mobile terminal20 has been connected to the car telephone 30, the user starts up theload situation inquiry program. In this case, the user is only requiredto input data on an object address in accordance with the instruction ofthe program unlike step S102 (S202). Step S204 which establishes theconnection is similar to S104, but differs from S104 in that the formeruses a radio communication line. Steps S208-S214 are exactly the same asS108-S114. Since the mobile terminal 20 transfers data on the longitudeand latitude of its current position informed by GPS 40 to theinformation server 21 without changing the data, the information server21 maps the area with the longitude and latitude to retrieve informationon the situation of the appropriate area. Step S216 which refers toinformation on the situation of a point on the way to the destinationduring travelling corresponds to S114 to thereby terminate the series ofsequencing operations.

An example in which the aged situation information is discarded and thenewest information is automatically loaded on the mobile terminal 20 atconstant intervals of time will be described next.

FIG. 10 shows a sequence of operations in which the mobile terminal 20inquires of the information server 21 periodically necessary situationinformation and downloads same. The difference between this sequence ofoperations and that of FIG. 9 will be described mainly in a contrastingmanner.

The sequence of steps S300 to S304 in which the mobile terminal 20reports positional information on its current place and destination tothe information server 21 is similar to the sequence of S200 to S204 ofFIG. 9. The information server 21 determines from the positionalinformation on the mobile terminal 20 in which area the mobile terminal20 is present, and stores that area as historical information. Theinformation server 21 then compares the current area in which the mobileterminal 20 is present and the previous area in which the mobileterminal 20 reported its previous positional information to determinewhether they coincide with each other (S308). If so, the informationserver determines that the mobile terminal 20 is still in the same areaas before and shifts its operation to interruption of the connectionwithout retrieving information on the situation (S314). This function isprovided to eliminate a waste of downloading the same information on thesituation when there is no situation in which the moving speed of themobile terminal is abnormally low compared to its normal moving speed,for example, when a change in the situation is slow compared to theintervals of time for inquiry and the mobile terminal 20 remainsstationary. Referring back to sequence S308, the description continues.If the result of the determination indicates non-coincidence, theinformation server determines that the mobile terminal 20 has moved tothe next area, downloads the situation information and performs thesequencing operations up to referring to the situation information(S310-S316), which are similar to the sequencing operations S208-S216 ofFIG. 9. The step S318 involves a re-inquiry determining process in whichthe mobile terminal starts up a timer, waits until a given count isreached, passes to step S304 unless there is a request for terminationfrom the user, and passes to a step S320 involving the termination ofthe process if there is a request for termination. While at S308 theexample of the function provided to eliminate the waste of downloadingthe same situation information has been illustrated, an example realizedby causing the information server 21 to manage the history of theinformation downloaded on the mobile terminal 20 and to download on themobile terminal 20 only information, which has not yet been downloadedon the mobile terminal 20, in response to an inquiry from the mobileterminal 20 may be incorporated easily into the above-mentioned sequenceof operations.

In the above, it has been described that the mobile terminal 20 accessesthe information server 21 at constant intervals of distance when thebeforehand loaded information has become old and the newest informationis required. Referring to FIG. 11, the embodiment which does not use themere distance from the starting point will be illustrated which realizesthat concept in which when a mobile terminal travels from the startingpoint to the destination through a series of areas into which positionson the ground are divided as blocks, an area containing the startingpoint is defined as starting area and, an area to which the mobileterminal moves from the present area is defined as next area among theareas through which the mobile terminal goes to the destination andsituation information on the next area adjacent to the present area isautomatically loaded one after another.

The difference between FIGS. 11 and 10 will be mainly described next. Asequence of S400-S402 performed until the inquiry program is started upis similar to that of FIG. 10. In FIG. 11, the mobile terminal 20calculates its current area from information on its present position andchecks whether the situation information on the above-mentioned nextarea has been already downloaded. If so, control passes to a terminationdetermining step S418. If not, that is, if the situation information onthe next area has not yet been downloaded, the positional information onthe next area is reported (S408). This positional information relates toa range indicated in longitude and latitude. Receiving this information,the information server 21 retrieves the situation information on thespecified area from the database and sends it to the mobile terminal 20.The mobile terminal 20 stores the situation information received fromthe information server 21 (S412). The connection is then cut (S414) soas to allow the user to refer to the situation information on the nextarea (S416). Control then passes to a termination determining step S418,which is similar to S318 of FIG. 10. Unless there is no request fortermination within a certain time, control passes to S404 where it isdetermined from the information on the current position whether there isany situation information on the next area. Also, at this step, when themobile terminal stops, the situation information on the next area mayget old. However, there is no problem arising when the user stops, forexample, at a restaurant if the user terminates the operation of thisprogram and starts up the program when the user restarts. The mobileterminal 20 may set an effective term to the situation informationdownloaded from the information server 21, periodically inquire of theinformation server whether the effective term has expired, and if so,downloads the newest situation information even when the user does notmove to the next area.

While in the above the next area has been described as being next to thecurrent area, the relationship which will be next described must besatisfied by the "next" area in order that the positional relatedinformation to be downloaded on the mobile terminal be significant, asdescribed in the above mentioned BACKGROUND OF THE INVENTION.

FIG. 12 illustrates the relationship between the moving speed of themobile terminal, data transfer rate and a quantity of data on an area tobe downloaded. First, assume that there are divided areas a, b and cwith the origin as a reference. In order to simplify the explanation,assume that the areas each take the form of a square having a sidelength of 1 m, and that a quantity of information data on each of theareas is constant or D (kilobytes). Let the data transfer rate be TR(kilobytes/s) and let the speed of the mobile terminal be V (m/s). Inthis case, the time T taken for loading information on one area is D/TR(s). The distance L through which the mobile terminal moves during thetime T is L=V*D/TR(m). When L is between 1 and 2*1, the area c must beselected as an area next to the origin of FIG. 12. The condition underwhich the nth area comes are expressed as V*D/(TR*1)-1<n<V*D/(TR*1).

The next area is determined by causing the CPU of the mobile terminal tosolve that conditional inequality. When the mobile terminal 20 is set ina car and used, the moving speed of the mobile terminal 20 is obtainedfrom an interface provided to report the current speed of the car fromthe speed measuring unit to the mobile terminal 20. Alternatively, themoving speed may be calculated from the distance through which the carmoved during a constant time, using the GPS. Other parameters may begiven as the initial conditions.

In the embodiment, downloading service information on the position orarea from the remote information server 21 connected through the publicnetwork was illustrated.

The technique which constitute the core of the invention includes easyretrieval of service information by the user as described before. Thefeatures of the above example lie in that the time taken for downloadingthe situation information is hidden from the user. An embodiment will bedescribed which when the service information is stored as compresseddata in a disk device built in the mobile terminal 20 and not in remotestorage and the time taken for its decompression is much, this time ishidden from the user and information on the appropriate area isretrieved immediately in accordance with the user's request.

FIG. 13 illustrates service information stored in RAM 12 and memory card18.

Compressed service information on the respective areas and serviceclassifications are stored in the names of compressed data n (n is anatural number; 1, 2, 3, 4, . . . ) in the memory card 18. Also storedin the memory card is directory information as information on thecorrespondence between the names of the compressed service informationon the respective area and service classifications and their addressesstored in the memory card 18. The compressed data are the onescompressed by various compression algorithms in which the datacompression rate is maximum for the respective types of data (text,image, voice).

RAM 12 stores only decompressed service information on the current area(current area information) and decompressed service information on thenext area (next area information) and also an area-compressed data namecorrespondence table 130, which is composed of the next respectivefields; that is, an area name field as the name of each area, forexample, described in the symbol "a-A" in FIG. 5; a serviceclassification field as a field expressing the classification of eachservice information; and a compressed data name field paired with itsservice information field and in which a corresponding compressed dataname is written.

Referring to FIG. 14, the operation chart for CPU 10 and its relatedelements in the present embodiment will be described next. FIG. 14 is anoperation chart which indicates the position of the mobile terminal, andthe timing between the user's retrieval of service information, CPUprocessing, and loading of compressed data between the disk and RAM.FIG. 14 will be described on the analogy to FIG. 11. The respectivemobile terminals correspond to the CPU while the information servercorresponds to the disk. The determination of the presence/absence ofsituation information on the next area (S404) corresponds to positiondetection (1100) and next area determination (1102); reporting ofpositional information on the next area (S408) corresponds to a dataloading request (1104); retrieval of situation information on aspecified area and its sending (S410) corresponds to a wait time (1106)and data loading (1108); storage of situation information on the nextarea (S412) corresponds to reporting the termination of the data loading(1110), and referring to the situation information (S416) corresponds toretrieval request (1114), retrieval (1116), and retrieval response(1118). There is no step corresponding to the decompressing process(1112). Those steps of the present chart will be described sequentially.The chart portions ranging from 1100 to 1112 are periodically repeatedby the timer function described at S418.

First, at 1100, it is determined on the basis of positional informationfrom GPS 40 in which area the mobile terminal is. At 1102, it is checkedwhether service information on the next area (next area information) isstored in RAM 12. If not, table 130 requests a disk such as memory card19 to load all the compressed data on the next area in their names(1104). The constant wait time (1106) is a relatively long time takenfrom receipt of a data load request to the stabilization of the rotationof the disk when the disk device has a rotating system and an auto poweroff function for power saving. The compressed data is disposed in a freearea of RAM 12 by data loading at 1108. Receiving a report oftermination of data loading (1110) from the disk, CPU 10 decompressesthe respective compressed data disposed in the memory area of RAM 12 torestore the next area information when it is in the present area (1112).FIG. 16 shows the format of the present area information and next areainformation. It is composed of area information which describes arelated area and a pair of service classification and serviceinformation proper.

When the position detecting function detects the movement of the mobileterminal to the next area, the current area information is released andprocessing for employing the next area information as the current areainformation is performed to use the small storage area of RAM 12effectively.

In this way, the next area information spread on RAM 12 in the previous"present" area is employed as the current area information. The userrequests retrieval of service information on the current area (1114).The appropriate service data is retrieved with the serviceclassification of FIG. 16 as a key (1116). The appropriate service datais then given to the user (1118).

While the present embodiment illustrated that the compress data isstored in the disk and that as described with reference to FIG. 9,situation information on a plurality of areas present before thedestination is received beforehand in the form of compressed data fromthe information server 21 and stored in the memory card 19. The use of amethod will be easily analogized in which information on a map and/orthe positions of shops as the base which do not greatly change is storedin a compressed form in a storage medium such as a CD-ROM whileinformation on rapidly changing road situation and/or commodity pricesis downloaded through communication lines from the remote informationserver and provided as multimedia information such as voice, text and/orimages.

When the compressed data is downloaded from the information server tothe mobile terminal, data having a higher compression rate will take alonger recompression time. Thus, if the time taken for decomposing thecompressed data having a higher compression rate employed to reduce thecommunication cost is so large that it cannot be neglected compared tothe data transmission time, the method of determining the next area asdescribed with reference to FIG. 12 must be changed. To this end, it maybe determined from an expression of time T of FIG. 12 plus the timetaken for decompressing the compressed data.

As described above, information on the positions of areas is stored inthe form of compressed data, for example, in a CD-ROM, and data on thenext area is loaded and decompressed in the present area to reduce thetime taken to retrieve necessary data in the next area. Thus, a methodof determining the next area will be easily understood even though it isnot described in detail.

The time T may be approximated by the sum of the wait time and thedecomposing time. Especially, a portable CD-ROM drive device must be ofa thin light-weight and power saving type, and the maximum torque of itsmotor can not be so large. Thus, the inertial moment can not be drivensufficiently and the rotation wait time is large. In this respect, theauto power off logic will be described referring to FIG. 15. This logicstarts when the disk access ends. First, the timer counter is cleared to0 (1000) and it is checked whether there is any request for disk access(1002). If so, this process ends and control passes to a disk accessprocess. If there is no request for disk access at 1002, it is checkedwhether the count of the timer counter has exceeded a predeterminedvalue (1004). If so, the power of the motor is turned off to stop therotation of the motor (1006). If not, after a given time (1008), thetimer count is incremented (1010), and then control passes to a step1002.

The above relates to the main application of the present invention tothe navigation system. Another embodiment will be described next whichinvolves the use of a mobile terminal as a shopping catalogue referencedevice, that is, of the type in which the consumer carries the mobileterminal into a department store, a shopping town, or an undergroundshopping center, obtains information on a favorite commodity through themobile terminal from a commodity database of the information server anduses such information as a reference for buying the commodity.

Radio accessing means in such embodiment is realized, for example, by aPHS (Personal Handyphone System). Thus, a cordless telephone isconnected in place of the car telephone 30 of FIG. 8. For the detectionof the position of the mobile terminal, a base station for a PHSdisposed in the campus determines the position of a nearby mobileterminal on the basis of the radio strength of the cordless telephone.Thus, the mobile terminal system is not required to have a positiondetector such as GPS 40. An active batch method is well known as suchposition detecting mechanism. As described above, it is improper tocause the user to input information on the position of a destination inthe mobile terminal used as a tool for referring to commodityinformation near a shop, as described above, as in the previousembodiment because it can not support impulse buying. The presentinvention is applicable to a system in which information which will bereferred to at the destination is loaded in the present area in order tosatisfy the immediate referrability of commodity information. The areadescribed above is logical compared to a cell, that is, a range (of anunobstructed viewing distance of about 100 m) which a single basestation covers, so that their correspondence is not required to be 1:1.As described above, when no destination is given, all the areas adjacentto the current area are selected as the next areas and information onthose areas are downloaded.

FIGS. 17A, 17B each show the relationship between the current area andits next areas. FIG. 17A is a developed view of a plane area, and showsthat when bB denotes the current area, aA, aB, aC, bA, bB, bC, cA, cB,and cC denote the next areas. While FIG. 17A is shown in two dimensions,the modification of its concept concerning the two-dimensionalarrangement to a three-dimensional area arrangement in which shops aredistributed in a plurality of floors will be easily seen. Since thestructure of areas is logical, it is unnecessary that the actual cell isa position and that the physical position is a short distance: forexample, a case in which an upper and a lower floor are connected by athrough elevator or a case in which a building is connected by aconnecting passageway to another building.

As described above, the correspondence between a cell and an area is notrequired to be fixed, but may be changed depending on the quantity ofinformation.

When areas are formed alternately as shown in FIG. 17B, the number ofnext areas is reduced. Thus, a quantity of information to be downloadedis reduced. If the next area determining method is used, an area whichis not next to the current area can be the new next area.

When there are many next areas in the above embodiment, some informationmay overflow from the memory of the mobile terminal 20, which will bedescribed next when an adjacent area is selected as the next area. Inthis case, a system is employed in which data on the histories ofservice classifications referred to in the area next to the current areaand its next area are downloaded in defending order of the number ofhistories, which implies providing service preferentially for customers.FIG. 18 shows a management table 180 to realize the present function inthe information server 22. In the current area field, the area name isdescribed. In corresponding adjacent area fields, the names of areasadjacent to the current area are described. In a service type field, thetype of service information, more specifically, a commodityclassification, is described. In a reference count field, the number oftimes of user's reference to the service information is described. Whilein FIG. 18 the corresponding fields are expressed in blocks, a hash maybe used to speed up the retrieval or they may be placed in a tree-likecorresponding relationship. Since those fields involves staticinformation excluding the reference count, specified values and/orinformation described at the start-up are not frequently updatedthereafter.

When the user refers to the appropriate information, the mobile terminal10 detects this fact and reports same to the information server 21.Receiving this information, the information server 21 increments thereference count. A sequence of operations which will be performedbetween the mobile terminal and the information server is similar to thesequence of operations of FIG. 10 except that information on thepositions of the destination and the current area at S306 of FIG. 10 isnot reported.

While in the above the information server 21 has been illustrated asperforming the management of the position of the mobile terminal 20 anddetermines service information to be loaded, a sequence of operationswhich includes performing such function on the side of the mobileterminal 20 will next be described with reference to FIG. 19.

Assume that the mobile terminal 20 is capable of obtaining informationon the position of a cell to which the mobile terminal 20 belongs by thePHS services. The mobile terminal 20 has information on thecorrespondence between the positions of the cells and areas which arethe logical units of a range on the service information to therebyspecify the current area. As described above, areas adjacent to thecurrent area are obtained from the current area, using table 180 (S500).Service information having a large reference count is selected from thereference counts in the appropriate area on table 180 (S502). The mobileterminal requests from the information server the selected serviceinformation in its service type (S504). Receiving this request, theinformation server retrieves the requested service information from thedatabase (S506) and sends the result of the retrieval to the mobileterminal (S508).

While the service information on all the areas adjacent to the currentarea is illustrated as loaded in the embodiment, an embodiment will bedescribed in which an area adjacent to the current area on a line ofextension which connects the previous and current positions is selectedas the next area on the basis of information on the positions of theprevious and current areas, and service information on the new adjacentarea is loaded on the mobile terminal 20.

FIG. 21 illustrates this concept. A black and a white dot express theprevious and current positions, respectively. For example, when thosepositions are expressed as data in a certain coordinate system,directional data are obtained by subtracting the previous positioncoordinates from the current position coordinates. A table whichindicates the directions of the areas adjacent to the current area isprepared and the adjacent area in the appropriate direction is selectedas the next area. FIG. 20 illustrates a sequence of operations performedbetween the mobile terminal 20 and the information server 21 in thepresent embodiment. First, the information server 21 periodicallyinquires of the mobile terminal 20 its position (S600). Receiving thisinquiry, the mobile terminal 20 checks whether this message is proper,detects its position, and sends information on its detected position tothe information server 21 (S602). Receiving this information, theinformation server 21 determines the next area, using theabove-mentioned method (S604). Unless service information on thedetermined next area has been sent to the mobile terminal 20, theinformation server 21 sends it to the mobile terminal (S606).

At S318 of FIG. 10, the timer is started up to give a small wait time.The timer time is a non-changing constant value, so that thecommunication to the information server 21 is periodical. An embodimentin which the timer time value is changed depending on the moving speedof the mobile terminal will be described next. The relation between themoving speeds of the mobile terminal and the timer time values is storedin the form of a table in the mobile terminal. The mobile terminalperiodically recognizes its current area, using the position measuringfunction of the GPS 40, calculates the moving speed thereof, using timeinformation from its built-in clock, and stores the average of themoving speeds thereof. Immediately before the timer is set, the mobileterminal refers to the average of the moving speeds thereof, searchesthe table for a corresponding timer time value, sets the timer at thistime value, and resets the average of the moving speeds thereof. Thus,when the user remains stationary at a position, the frequency ofreporting to the information server 21 and the communication cost arereduced.

While the above description is made on the assumption that the number ofaccess points to the information server 21 is one, the informationserver may have a plurality of access points. At this time, by storingdata on the positions of the respective access points in the mobileterminal, and calculating and comparing the distances between thecurrent position and the respective access points, using GPS 40, thenearest access point is known. The communication fee is reduced byaccessing the information server 21 with a dial number at another accesspoint as the mobile terminal moves compared to accessing the informationserver at the distance between the current position and the access pointused at present.

Another embodiment in which a plurality of information servers 21 isprovided is conceivable. Also in this case, there is a plurality ofaccess points as in the above case. When there are different servicetraders having corresponding information servers 21, their contents ofservice are different and hence it is not appropriate to select themautomatically and individually. In such a case, when the mobile terminal20 detects an information server 21 which reduces the communication costas the mobile terminal 20 moves, the mobile terminal 20 is required toconfirm whether the user assents to change the information server 21 andits contents of the service to the detected information server and itsservice, and if the user assents, it does so.

The above description illustrates the example in which mobile serviceinformation which will be referred to in the from of a response toreporting information on a road along which the mobile terminal 20travels is sent beforehand from the information server 21 to the mobileterminal 20. One example of a sequence of operations in which when asituation occurs which will influence the route along which the mobileterminal 20 travels, the information server 21 detects this fact andsends appropriate service information to the mobile terminal will bedescribed with reference to FIG. 22.

The information server 21 monitors possible occurrence of situationinformation at all times (S740). Since a sequence of operationsincluding providing positional information periodically for theinformation server (S700-S708, S728) is similar to that of the aboveembodiments, it will be omitted. Receiving the positional information,the information server 21 presumes the route along which the mobileterminal travels, on the basis of the positional information received sofar (S710). When the information server 21 is capable of presuming theroute and there is no need for inquiring more information from themobile terminal and there is no service information, the informationserver 21 cuts the connection without sending any information to themobile terminal (S712). Thereafter, the information server 21 monitorspossible occurrence of situation information. When such informationoccurs, the information server 21 picks up all the mobile terminalswhich the situation information will influence from information on thepresumption of the route prepared for each mobile terminal. If there areno appropriate ones, the information server 21 waits for a report ofpositional information from some mobile terminals 20 (S714). If there isany mobile terminal which the situation information would influence, theinformation server predicts its influence, and prepares for eachterminal as service information bypath information about avoidance fromsuch influence. The information server schedules the timing of sendingthe appropriate service information and establishes the connection to anappropriate terminal when the appropriate time is reached (S718), andsends the appropriate service information with an indication "urgent" tothe appropriate mobile terminal (S718). Thereafter, the informationserver 21 cuts the connection (S720) to prepare for receiving a reportof positional information and/or a possible occurrence of furthersituation information. Receiving the service information so sent, themobile terminal 20 views the indication "urgent" added to the serviceinformation and presents the appropriate service information to the user(S724). Seeing this service information, the user changes the route inaccordance with the guide of the service information.

While in the above described sequence, the user inputs data on thedestination when the inquiry program has started up, a sequence ofoperations in which no inputting of information on the destination bythe user is required will be described below.

The mobile terminal 20 having the built-in GPS has a positionalinformation history managing function, and a system file which storespositional information. When supply of the power starts (S800), themobile terminal 20 writes positional information periodically into thesystem file (S801). The file has an upper limit of an amount ofpositional information to be stored. When a stored quantity of thepositional information reaches the upper limit, the file is used byagain from its head by overwriting. At this time, positional informationand the time are both stored. When the inquiry program is started up(S802), the mobile terminal reads positional information a given timebefore from the file and reports it to the information server (S806).Receiving this information, the information server 21 predicts from theinformation on the route along which the mobile terminal 20 travels, andsends necessary service information, if any, to the mobile terminal(S808). Thereafter, the mobile terminal periodically reports its currentplace to the information server (S816, S806).

By such composition, timely information on the situation which the userof the mobile terminal needs on the spot can be retrieved immediately.More specifically, assume that this device is applied to a carnavigation system. When gasoline is desired to be fed to the car duringdriving, the position of a nearby gas station, the gasoline maker andprice, etc., are displayed on the spot. Thus, appropriate fuelling isachieved at his judgement. That is, by receiving convenient information,the user can do comfortable shopping during driving. Since the user isable to avoid implication into a traffic jam and/or use a shortcutand/or byway, the user is able to reach the destination rapidly,advantageously.

The present embodiment relates to a system composition in which no radiocommunication device and/or position recognizing device are annexed tothe mobile terminal. Thus, by this embodiment, the cost is reducedcorrespondingly, so that an inexpensive navigation system is providedfor the user, advantageously. Since the communication means used fordownloading various service information mentioned above is the publictelephone network, a large amount of high quality data for multimedia isavailable in a short time at an inexpensive price. Since the publictelephone network is spread nationwide and a communicationinfrastructure, it is usable anywhere in this country, advantageously.

When the destination of the user who uses the navigation system is notfixed or far away, the user is able to immediately retrieve the newestservice information on the spot as requested at whatever speeds the usermay move. In order to download the service information, there is no needfor taking the trouble to come to a place where a fixed access point tothe public line such as for the public telephone is provided. Inaddition, since downloading is performed automatically, the user is notrequired to take the trouble to perform the downloading operation,advantageously. Since the already downloaded information is preventedfrom being again downloaded by downloading the newest serviceinformation automatically (periodically), no excess communication fee isrequired to be paid for downloading useless information, advantageously.

Advantageously, by carrying the mobile terminal even when the user walksor uses a public traffic service without mounting it only on a car, thesystem which is capable of receiving navigation service is capable ofimmediately retrieving information on any particular spot withoutreducing consumption of the battery power. In addition, by downloadingonly rapidly changing service information from a remote informationserver and storing service information which does not rapidly change inthe built-in storage, the communication cost is reduced, advantageously.

Information related to commodities which the user liked at a glance in acommodity information reference system at a shopping center can beimmediately referred to on the spot. Furthermore, by the composition ofa logical area, a memory quantity in the mobile terminal is reduced,advantageously.

By filtering information to be downloaded with information in the movingdirection of the mobile terminal, the communication cost and the storagecapacity are reduced, and hence the overhead in the present process isreduced, advantageously.

In an arrangement to which a remote work support system is applied, theoperator is able to obtain information on work in the work area beforethe operator arrives at the work area, using the present mobileterminal, and is able to start his work as soon as the operator arrivesat the work area, so that the working efficiency is improved. Byprovision of a cable which connects a work area monitoring device and acommand center, downloading support information on the mobile terminalis only required and there is no information to be communicated from themobile terminal to the command center thorough a radio system. Thus, theconsumption power of the mobile terminal is reduced.

Since in a refuge guidance system detailed information on a refuge routefor a refugee with a mobile terminal to take can be given to the refugeethrough multimedia information, a person who has no appropriateknowledge, for example, about the structure of a complicated buildingsuch as underground shops is able to avoid being gotten into a panic andescape rapidly into a safety area. Thus, possible human damage due to adisaster such as a fire and/or earthquake is minimized, advantageously.

Since in a meeting reservation system guests are called into a meetingroom of a company as soon as they arrives at the company and informationnecessary for the meeting is distributed to the respective guests whenthe guests gather, the wait time before the meeting is reduced and themeeting is started immediately, advantageously. Since in the presentembodiment arrival of the guest is not inquired of the informationserver, the overhead about the inquiry is eliminated and the powerconsumption of the battery is minimized, advantageously.

By sending time-limited service information spontaneously to the mobileterminal, a shop owner who is an information provider is able to drawcustomers to his shop, and the user of the mobile terminal is able toimmediately retrieve a shop which provides service and/or commoditieswhich satisfies his taste and/or budget from the service information,advantageously.

Using the attributes of the user's mobile terminal, loadinginappropriate information on the mobile terminal is avoided to therebyavoid the user's reference to inappropriate information. Conversely, byloading appropriate information on the appropriate mobile terminalbeforehand, its user is able to immediately refer to appropriateinformation depending on the situation as requested.

When a program to be used or data to be referred to are fixed in an areaor when their correlation is high, the executing performance of themobile terminal with a virtual storage mechanism is improved to therebyprovide the user with a comfortable computer environment.

According to the present invention, a communication method whichprovides necessary information for the user on a real time basis and amobile terminal preferred for this communication method are provided.

According to the present invention, a communication method whichinformation to be provided for the user is transferred to the user atappropriate timing and a mobile terminal preferred for execution of thiscommunication method are provided.

What is claimed is:
 1. A method of providing information from aninformation server to a mobile terminal in a system which includes themobile terminal, the information server which is connected to adatabase, a network connected to the information server, and a terminalconnected to the network for providing various information for theinformation server, said method comprising the steps of:connecting themobile terminal to the network and when information on the currentlocation and destination of the mobile terminal is input to the mobileterminal, reporting the input information on the current location anddestination to the information server through the network; causing theinformation server to determine the area surrounding an expected routeincluding the current location and destination of the mobile terminalwhen the information server receives from the mobile terminal a reportincluding information on the current location and destination of themobile terminal, and to send service information including priceinformation of a product provided in an area corresponding to the areasurrounding the expected route through the network to the mobileterminal; and causing the mobile terminal to store the received serviceinformation including price information of a product provided in thecorresponding to the area surrounding the expected route, to cut theconnection to the network and to output the previously stored serviceinformation in accordance with the user's request.
 2. A method ofproviding information from an information server to a mobile terminal ina system which includes the mobile terminal, the information serverwhich is connected to a database, a network connected to the informationserver, and a terminal connected to the network for providing variousinformation for the information server, wherein the mobile terminal isconnected to a portable telephone set so as to be connected to thenetwork, and connected to a GPS which periodically stores information onits position in a memory, said method comprising the steps of:the mobileterminal receiving information regarding the present location of the GPSfrom the GPS and input information on a destination of the mobileterminal; the mobile terminal informing, through the network, theinformation server of the received information regarding the currentlocation and the destination of the mobile terminal; the informationserver, having received from the mobile terminal, information regardingthe current location and destination of the mobile terminal, theinformation server determining the area surrounding an expected routeincluding the current location and destination, and sending serviceinformation including price information of a product provided in an areacorresponding to the area surrounding the expected route through thenetwork to the mobile terminal; and the mobile terminal storing thereceived service information including the price information of aproduct in the area corresponding to the area surrounding the expectedroute, cutting the connection to the network, and outputting thepreviously stored service information in accordance with the user'srequest.
 3. A method according to claim 2, further comprising the stepsof:the mobile terminal periodically sending information regarding thecurrent location thereof through the network to the information server;and the information server periodically sending the service informationthrough the network to the mobile terminal.
 4. A method according toclaim 3, further comprising the steps of:when the information serverreceives the information regarding the current location of the mobileterminal from the mobile terminal, the information server comparing theservice information regarding the area surrounding the expected routepreviously sent to the mobile terminal and further service informationregarding an area surrounding the expected route to be sent; and whenthe further service information regarding the area surrounding theexpected route to be sent is different from that of the serviceinformation previously sent, the information server sending the furtherservice information regarding the area to be sent through the network tothe mobile terminal.
 5. A method according to claim 3, wherein themobile terminal performs the steps of:producing history information byperiodically storing information regarding the position of the mobileterminal; determining the next area surrounding the expected route fromthe produced history information; reporting information regarding thenext area surrounding the expected route to the information serverthrough the network; and inquiring of the information server serviceinformation regarding the next area surrounding the expected route.
 6. Amethod according to claim 5, further comprising the steps of:storing theservice information regarding the area surrounding the expected routeincluding the current location and destination of the mobile terminalsent from the information server, as compressed data, in an externalstorage of the mobile terminal; reading the service information on thenext area surrounding the expected route stored in the external storagewhen the determined service information on the next area surrounding theexpected route is not stored in a RAM of the mobile terminal;decompressing the read service information; and storing the decompressedinformation in the RAM of the mobile terminal.
 7. An informationproviding system, comprising:a mobile terminal; an information serverconnected to a database; a network connected to the information server;and a terminal connected to the network for providing variousinformation for the information server, wherein:the mobile terminal isconnected to the network, and when the current location and destinationof the mobile terminal is input to the mobile terminal, the mobileterminal reports the input information regarding the current locationand destination to the information server through the network; theinformation server determines the area surrounding an expected routeincluding the current location and destination of the mobile terminalwhose information was received from the mobile terminal, and sendsservice information including price information of a product provided inan area corresponding to the area surrounding the expected route throughthe network to the mobile terminal; and the mobile terminal stores thereceived service information including the positional informationcorresponding to the area surrounding the expected route, and outputsthe stored service information on a real time basis in accordance withthe user's request.
 8. An information providing system, comprising:amobile terminal; an information server connected to a database; anetwork connected to the information server; and a terminal connected tothe network for providing various information for the informationserver; and a GPS connected to the mobile terminal for periodicallystoring a position thereof in memory; and whereinwhen the mobileterminal receives information regarding the present location of the GPSfrom the GPS and information regarding a destination, the mobileterminal informs the information server of the received informationregarding the current location and destination of the mobile terminalthrough the network; when the information server receives from themobile terminal information regarding the current location anddestination, the information server determines the area surrounding theexpected route including the current location and destination of themobile terminal, and sends service information including priceinformation of a product in an area corresponding to the areasurrounding the expected route through the network to the mobileterminal; and the mobile terminal stores the received serviceinformation including the positional information corresponding to thearea surrounding the expected route, cuts the connection to the network,and outputs the stored service information in accordance with the user'srequest.
 9. An information providing system according to claim 8,wherein the mobile terminal periodically sends information regarding thecurrent location thereof through the network to the information server,and the information server periodically sends the service informationthrough the network to the mobile terminal.
 10. An information providingsystem according to claim 9, wherein when the information serverreceives the information regarding the current location of the mobileterminal from the mobile terminal, the information server compares theservice information regarding the area surrounding the expected routepreviously sent to the mobile terminal and further service informationon an area surrounding the expected route to be sent presently, and whenthe further service information regarding the area surrounding theexpected route to be sent presently is different from the serviceinformation sent previously, the information server sends the furtherservice information regarding the area surrounding the expected route tobe sent presently through the network to the mobile terminal.
 11. Aninformation providing system according to claim 9, wherein the mobileterminal produces history information by periodically storinginformation regarding the position of the mobile terminal, determinesthe next area surrounding the expected route from the produced historyinformation, reports information regarding the next area surrounding theexpected route to the information server through the networks andinquires of the information server service information regarding thenext area surrounding the expected route.
 12. An information providingsystem according to claim 11, wherein:the service information regardingthe area surrounding the expected route including the current locationand destination of the mobile terminal sent from the information serveris stored, as compressed data, in an external storage of the mobileterminal, the service information regarding the next area surroundingthe expected route stored in the external storage is read when thedetermined service information regarding the next area surrounding theexpected route is not stored in a RAM of the mobile terminal, the readservice information is decompressed, and the decompressed information isstored in the RAM of the mobile terminal.
 13. A mobile terminal,comprising:an input unit connected to a portable telephone set so as tobe connected to a network, said input unit being connected to a GPSwhich stored information regarding the position thereof periodically ina memory, said input unit receiving the information regarding thecurrent location of the GPS from the GPS and a destination of the mobileterminal; a sender for sending the received information regarding thecurrent location and destination of the mobile terminal through theportable telephone set to an information server connected to thenetwork; a receiver for receiving from the information server serviceinformation including price information of a product provided in thearea surrounding an expected route including the current location anddestination of the mobile terminal; storage for storing the serviceinformation including the price information of a product in the areasurrounding the expected route received from the receiver; and an outputfor outputting the service information stored previously in the storagein accordance with the user's request.
 14. A mobile terminal accordingto claim 13, further comprising a timer for periodically inquiring ofthe information server information regarding the current location of themobile terminal.
 15. A mobile terminal according to claim 14, furthercomprising control means for producing history information byperiodically storing information regarding the position thereof, and fordetermining the next area surrounding the expected route from theproduced history information, andwherein the sender informs theinformation server of the determined next area surrounding the expectedroute.
 16. A mobile terminal according to claim 15, furthercomprising:an external storage for storing, as compressed data, theservice information regarding the area surrounding the expected routeincluding the current location and destination of the mobile terminalsent from the information server; and a control unit for reading serviceinformation regarding the next area surrounding the expected routestored in the external storage when the determined service informationregarding the next area surrounding the expected route is not stored ina RAM of the mobile terminal and for decompressing the read serviceinformation, wherein the decompressed information is stored in the RAM.